Broadband High-resolution Spectroscopy With Fabry-perot Quantum Cascade Lasers

Wysocki, Gerard

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https://hdl.handle.net/2142/51119 Copy

Description

Title

Broadband High-resolution Spectroscopy With Fabry-perot Quantum Cascade Lasers

Author(s)

Wysocki, Gerard

Contributor(s)

Wang, Yin

Issue Date

2014-06-17

Keyword(s)

Instrument/Technique Demonstration

Abstract

"Simultaneous spectroscopic detection of large molecules with broad ro-vibrational spectra, and small molecules with well-resolved narrow spectral lines requires both broadband optical frequency coverage ($>$50 \wn) and high resolution ($<$0.01 \wn) to perform accurate spectral measurements. With the advent of room temperature, high power, continuous wave quantum cascade lasers (QCLs), high resolution mid-IR spectrometers for field applications became feasible. So far to address the broadband spectral coverage, external cavity (EC) QCLs with $>$100 \wn tuning ranges have been spectroscopic sources of choice in the mid-IR; however EC-QCLs are rather complex opto-mechanical systems, which are vibration-sensitive, and construction of robust transportable systems is difficult. In this work we present a new method of performing broadband mid-IR spectroscopy using two free-running Fabry-Perot (FP) QCLs to perform multi-heterodyne down-conversion of optical signals to RF domain. The sample transmission spectrum probed by one multi-mode FP-QCL is down-converted to the RF domain through an optical multi-heterodyne process using a second FP-QCL as the local oscillator\footnote{Y. Wang, M. G. Soskind, W. Wang, and G. Wysocki, ""High-resolution multi-heterodyne spectroscopy based on Fabry-Perot quantum cascade lasers,"" Appl Phys Lett 104, 0311141-0311145 (2014)}. Both a broadband multi-mode spectral measurement as well as high-resolution ($~$15 MHz or $~$0.0005 \wn) absorption spectroscopy of NH$_{3}$ and N$_{2}$O are demonstrated and show potential for all-solid-state FP-laser-based spectrometers for chemical sensing."

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/51119

DOI

https://doi.org/10.15278/isms.2014.TJ07

Copyright and License Information

Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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